[LyX/master] Fix a cmake monolithic build error

[Georg Baum]

commit 1900eb28343eb004275df21f2157a3727dce6fcf
Author: Georg Baum <b...@lyx.org>
Date:   Mon Nov 16 21:39:03 2015 +0100

    Fix a cmake monolithic build error
    
    N_() is a preprocessor macro to mark translatable static strings. It is not 
a
    good idea to also name a class member variable N_: It did only work in the
    other build configurations because gettext.h was not included.

diff --git a/src/Compare.cpp b/src/Compare.cpp
index 048feba..2344f25 100644
--- a/src/Compare.cpp
+++ b/src/Compare.cpp
@@ -228,7 +228,7 @@ class Compare::Impl {
 public:
        ///
        Impl(Compare const & compare)
-               : abort_(false), N_(0), M_(0), offset_reverse_diagonal_(0),
+               : abort_(false), n_(0), m_(0), offset_reverse_diagonal_(0),
                  odd_offset_(0), compare_(compare),
                  old_buf_(0), new_buf_(0), dest_buf_(0), dest_pars_(0),
                  recursion_level_(0), nested_inset_level_(0), D_(0)
@@ -306,9 +306,9 @@ private:
        void writeToDestBuffer(ParagraphList const & copy_pars) const;
 
        /// The length of the old chunk currently processed
-       int N_;
+       int n_;
        /// The length of the new chunk currently processed
-       int M_;
+       int m_;
        /// The offset diagonal of the reverse path of the
        /// currently processed chunk
        int offset_reverse_diagonal_;
@@ -612,7 +612,7 @@ Compare::Impl::SnakeResult 
Compare::Impl::retrieveMiddleSnake(
        if (os[k].empty() && os_r[kk].empty()) {
                // No, there is no snake at all, in which case
                // the length of the shortest edit script is M+N.
-               LATTEST(2 * D - odd_offset_ == M_ + N_);
+               LATTEST(2 * D - odd_offset_ == m_ + n_);
                return NoSnake;
        }
 
@@ -634,12 +634,12 @@ int Compare::Impl::findMiddleSnake(DocRangePair const & 
rp,
        DocPair & middle_snake)
 {
        // The lengths of the old and new chunks.
-       N_ = rp.o.length();
-       M_ = rp.n.length();
+       n_ = rp.o.length();
+       m_ = rp.n.length();
 
        // Forward paths are centered around the 0-diagonal; reverse paths
        // are centered around the diagonal N - M. (Delta in the article)
-       offset_reverse_diagonal_ = N_ - M_;
+       offset_reverse_diagonal_ = n_ - m_;
 
        // If the offset is odd, only check for overlap while extending forward
     // paths, otherwise only check while extending reverse paths.
@@ -655,7 +655,7 @@ int Compare::Impl::findMiddleSnake(DocRangePair const & rp,
        nrs.reset(DocIterator());
 
        // In the formula below, the "+ 1" ensures we round like ceil()
-       int const D_max = (M_ + N_ + 1)/2;
+       int const D_max = (m_ + n_ + 1)/2;
        // D is the number of horizontal and vertical steps, i.e.
        // different characters in the old and new chunk.
        for (int D = 0; D <= D_max; ++D) {